code: def createRNN(rnn_type, nlayers, hidden_size):
      _rnn_type = rnn_type.lower()
      if _rnn_type == "lstm":
          return [
              LSTM(hidden_size, return_sequences=True)
              for layer in range(nlayers)
          ]
      elif _rnn_type == "gru":
          return [
              GRU(hidden_size, return_sequences=True)
              for layer in range(nlayers)
          ]
      elif _rnn_type == "simplernn":
          return [
              SimpleRNN(hidden_size, return_sequences=True)
              for layer in range(nlayers)
          ]
      else:
          raise Exception("Only support lstm|gru|simplernn")
  
imports: from bigdl.nn.layer import Layer
  from zoo.pipeline.api.keras.layers import *
  from zoo.models.common import ZooModel
  from zoo.common.utils import callZooFunc
  from zoo.pipeline.api.keras.engine import ZooKerasLayer
  from zoo.pipeline.api.keras.models import Model
label_desc: Use image node_id 1 for calling a global function with example usage: createRNN(rnn_type, nlayers, hidden_size) and returns: unknown, unknown, unknown